Loose-leaf hinge perforation



P. CRAVITZ March '24,. 1931.

Filed Sept. 25. 1929 Patented Mar. 24;, 1931 warren stares rarest orricr.

PHILIP CRAVITZ, or Los ANGEL-ES, CALiFORNIA noose-LEAF HINGE rEnronA'rIoN Application filed September 25, 1929. Serial No. 394,997.

My invention relates to loose leaf hinge perforations, and more particularly to the provision of a slit in association with the round perforation of a loose leaf which receives the binder ring or pin, whereby said slit allows the paper to yield transversely of the sheet to prevent tearing of the perforation, thus bringing into use the resilient characteristic of the leaf.

The principal object of my invention is to provide a loose leaf having a pin-or ringreceiving perforation, with a slit associated therewith, either adjacent thereto or intersecting said perforation but in no case running to the edge of the paper; to provide illustrated the same on the accompanying sheet of drawings, in which:

Figure 1 is a fragmentary portion of a loose leaf showing two regular perforations with slits associated therewith;

Figure 2 is a fragmentary view showing the operation of the slit under strain in the direction of the arrow;

Figure 8'is a fragmentary view of a leaf showing a slit intersecting the perforation;

and

Figure 4 showsportions of two die members for simultaneously perforating and slitting a sheet.

Referring in detail to the drawings, the usual perforation is designated 5 in all places on the drawings. In Figs. 1 and 2, the slit is designated 6 in all places. In Fig. 3, the slit is designated 7 and is shown intersecting the perforation 5. In no case does the slitrun out through the edge of the paper. This couldcnot be, as it would prevent the desired function. In Fig. 2, I have illustrated how the slit and surrounding paper function when any strain is applied to the leaf in the direction of the arrow. It will be seen that con siderable yielding is possible before any tearing takes place, and in most instances is suflicient to prevent the tearing out through the edge, either from the slit, or from the perforation. As the slit is thus, under strain, ex panded or distorted, the resilient property 5 of the paper is brought into play and there is sufficient give or yielding toprevent tearing and'as soon as the strain is released, the leaf returns to normal. I

In Fig. 4 I have shown two portions of two dies for forming the perforations and the slits together. The malemember of the dieis designated 8 and the female member is designated 9. Thepunch for the perforation is designated 10 and the knife is design ated 11, while in the female die member the hole is designated lOand the slot 11. It

.will be clear and well understood that it is asimple matter to provide the dies for forming the combination of perforation and slit, 7

either with the slit intersecting the perforation, or simply in close proximity thereto.

I do not limit my invention to exact details shown for descriptive purposes, realizing' that changes can bemade' without departing from the spiritof'the invention, except as I may be limited by the hereto appended claim.

I claim: A loose leaf for binders having a perfora-" o tion to receive the holding element of the binder and having a straight slit associated with said perforation and parallel throughout its length with the edge of the paper for the purpose of allowing the leaf to yield under strain transversely thereof to prevent tearing of theleaf, said slit being wholly within the edges of the leaf;

Si ned at Los Angeles, Los Angeles County, (Ia-lifornia, this 20th day of September, 1929.

. PHILIP GRAVITZ. 

